Wooden I-beams are widely used in the construction industry in most industrially advanced countries and are intended particularly for supporting formwork, preferably for roofs.
I-beams, whether wooden, metal or combined, are traditionally installed on two levels, a lower level of beams supported directly by props and an upper level of beams arranged perpendicularly to the former and supported on the first ones.
Wooden I-beams are normally joined together by nailing. This is a laborious, though effective system which, apart from its simplicity and adaptability, has many drawbacks, such as a shortening of the service life of the beams through the deterioration that is caused by the action of the nails, by disassembly and removal of the nails, which require considerable manpower, and by the fact that it is difficult to quantify the strength of the joint, since this depends on many variable factors, such as the diameter of the nail, the angle and depth of nailing, the state of the wood etc.
In addition to the procedure for connecting wooden I-beams by nailing, other connection systems are also known, such as making clamps of various kinds by using threaded bolts and clamping nuts, as well as wedge systems. In all these cases, manual clamping is required, which therefore provides discretion and therefore variability.